Magnetic field antenna

Abstract

A magnetic field antenna that provides high efficiency and a compact form factor. Electromagnetic shielding of electrical components used in the antenna is provided, and one embodiment of the invention is a wireless battery-free communications earplug.

What is claimed is: 
     
       1. A magnetic field antenna comprising:
 an earplug body having a distal end and a proximal end; 
 a magnetic core section within the earplug body; 
 an antenna coil having at least one turn wrapped at least partially around the magnetic core section; 
 at least one electrical component within the earplug body and electrically coupled to the antenna coil; and 
 a magnetic cap at the distal end of the earplug body, the magnetic cap magnetically coupled to the magnetic core. 
 
     
     
       2. The magnetic field antenna of  claim 1 , wherein the magnetic cap includes a vent channel to vent static pressure within the earplug body. 
     
     
       3. The magnetic field antenna of  claim 2 , in which the earplug body has an outer surface comprising a cover adjacent to the distal end of the earplug body and a base adjacent the proximal end of the earplug body. 
     
     
       4. The magnetic field antenna of  claim 1 , in which the at least one electrical component comprises a speaker. 
     
     
       5. The magnetic field antenna of  claim 1 , in which the at least one electrical component comprises at least one capacitor connected in parallel with the antenna coil. 
     
     
       6. The magnetic field antenna of  claim 1 , in which the at least one electrical component comprises a microphone. 
     
     
       7. The magnetic field antenna of  claim 1 , further comprising a loop transmitter comprising a coil of wire. 
     
     
       8. A magnetic field antenna comprising:
 an earplug body having a distal end and a proximal end; 
 a magnetic core section within the earplug body; 
 an antenna coil having at least one turn wrapped at least partially around the magnetic core section; 
 at least one electrical component within the earplug body and electrically coupled to the antenna coil; and 
 a magnetic shunt within the earplug body, the magnetic shunt magnetically coupled to the magnetic core. 
 
     
     
       9. The magnetic field antenna of  claim 8 , wherein the magnetic shunt is at least partially magnetically shunting the at least one electrical component to provide at least partial magnetic shielding of the at least one electrical component. 
     
     
       10. The magnetic field antenna of  claim 8 , wherein the earplug body has an outer surface comprising a cover adjacent to the distal end of the earplug body and a base adjacent the proximal end of the earplug body. 
     
     
       11. The magnetic field antenna of  claim 8 , wherein the at least one electrical component comprises a speaker. 
     
     
       12. The magnetic field antenna of  claim 8 , wherein the at least one electrical component comprises at least one capacitor connected in parallel with the antenna coil. 
     
     
       13. The magnetic field antenna of  claim 8 , wherein the at least one electrical component comprises a microphone. 
     
     
       14. The magnetic field antenna of  claim 8 , further comprising a loop transmitter having a coil of wire. 
     
     
       15. A magnetic field antenna comprising:
 an earplug body having a distal end and a proximal end; 
 a magnetic core section within the earplug body; 
 an antenna coil having at least one turn wrapped at least partially around the magnetic core section; 
 at least one electrical component within the earplug body and electrically coupled to the antenna coil; and 
 a magnetic eartip adapter, the magnetic eartip adapter magnetically coupled to the magnetic core. 
 
     
     
       16. The magnetic field antenna of  claim 15 , wherein the eartip adapter is positioned on the proximal end of the body and is acoustically coupled to the at least one electrical component. 
     
     
       17. The magnetic field antenna of  claim 15 , in which the earplug body has an outer surface comprising a cover adjacent to the distal end of the earplug body and a base adjacent the proximal end of the earplug body. 
     
     
       18. The magnetic field antenna of  claim 15 , in which the at least one electrical component comprises a speaker. 
     
     
       19. The magnetic field antenna of  claim 15 , in which the at least one electrical component comprises at least one capacitor connected in parallel with the antenna coil. 
     
     
       20. The magnetic field antenna of  claim 15 , in which the at least one electrical component comprises a microphone. 
     
     
       21. The magnetic field antenna of  claim 15 , further comprising a loop transmitter comprising a coil of wire.